In the late 1970's or early 1980's U.S. automobile manufacturers switched over to "unibody" type construction where the prior practice of having a massive automobile frame, and a separate lighter weight automobile body secured to the frame was discontinued. Instead, a "unitary body and frame" construction started to be used in the manufacture of American cars. This type of automobile construction technique had previously been used in Europe; and accordingly, many so-called "bench" systems were imported from Europe for the purposes of repairing damaged vehicles. These bench systems were and are massive, and involve the steps of holding or clamping the vehicle, measuring the departures from desired locations of the deformed parts, and applying restoring forces to bring the parts back to their original relative locations. However, many garages in the United States had floor anchor tie-down "pots" which they had previously been using for the repair of vehicles. Accordingly, the costly investment in the European type bench systems would have constituted an additional and duplicate expense.
Accordingly, one object of the present invention is to provide a viable alternative to the European bench systems, and one which would permit the use of pre-existing floor anchor tie-down pots or the like.
From another standpoint, the prior art includes various automobile repair tools such as those shown in G. N. Chartier, U.S. Pat. No. 3,340,720, and L. Eck, U.S. Pat. No. 3,338,083. These are relatively massive and elaborate systems for repairing damaged automobiles. Certain simpler types of power posts are also known, see W. K. Haggarty, U.S. Pat. No. 3,566,667 granted Mar. 2, 1971; however, these have generally been relatively limited in their functions and capability.
From a broader aspect, therefore, an important object of the present invention is to provide a relatively lightweight power post, which is compatible with the tie-down arrangements included in many garages or automobile repair facilities, and which also has the capability of providing multiple pulls and the flexibility of controlling these various pulls, without the need for the elaborate bench-type European equipment which is exceedingly massive, heavy, and expensive.